Many companies and network operators deploy common carrier mobile communication systems in almost every country around the world. Many of those network operators offer international roaming to their subscribers traveling abroad, and to travelers visiting their territory who use their foreign mobile phones. Such an offering enables public mobile network (PMN) subscribers to use their mobile phones within the PMNs other than their own, such as the networks present in territories other than those covered by the network to which they normally subscribe.
Typically the network operators enter preferred bilateral roaming agreements (“partnerships”) with each other that include more favorable roaming charges than those offered operators with whom they have established no such partnerships. Therefore, “preferred” visited networks are those that the home network prefers its outbound roamers to register with, when traveling outside their home coverage area, normally by virtue of such a partnership. Non-partner networks are “non-preferred” networks. Hence, the network operators can maximize their margins and the roamers can get more attractive roaming rates and better services if roamers roam on their home mobile operator's preferred (or partner) networks.
Subscribers may roam in one or more visited network(s) (i.e. Visited Public Mobile Networks (VPMN)) that may or may not be in the same country as their home network (i.e. Home Public Mobile Networks (HPMN)). In some cases a “non-preferred” VPMN may manage to get the subscribers from the HPMN, primarily due to “preferred” VPMN's failure in radio coverage, or manual selection by the subscriber of HPMN. This may also be due to traffic distribution by the HPMN Traffic Redirection (TR) (or Steering of Roaming (SoR)). Sometimes the HPMN operators use TR techniques to control the traffic distribution of the roamers among VPMNs in a country so that the “preferred” VPMN gets a higher percentage of the HPMN's roaming traffic as compared to the “non-preferred” VPMNs. However, these TR techniques may deprive the non-preferred VPMN operators of inbound roaming revenues. In some cases, these deprived VPMN operators may even have a partnership with the HPMN and be one of the “preferred” networks. In addition, TR technique, which typically functions by rejecting registration attempts, timing out or aborting the handset's attempt to register on a new VPMN, can generate network errors on the subscriber's mobile handset's radio interface. This compels the mobile handset to re-initiate a number of registration attempts, which unnecessarily overloads the network interface between the HPMN and the VPMN.
In some cases, competing and “non-preferred” VPMN operators may deploy a form of TR at their end to retain the inbound roamers (i.e. subscribers of HPMN) by stopping them from leaking out of their network. This decreases the revenues for other VPMN operators. The TR that these VPMN operators deploy is actually an inbound TR (ITR) solution to retain the inbound roaming subscribers.
The prior art also provides Anti-TR techniques designed to improve the chances of an inbound roamer registering successfully at a VPMN even when an HPMN is applying the TR against the VPMN. Other prior art techniques provide an anti-ITR system to counter a competitor VPMN's ITR attempt. One or more earlier filings provided integrated solutions to achieve the desired traffic redirection. In one case, the ITR and anti-TR solutions were integrated to handle the situation where an HPMN HLR issues a rejection error message to a VPMN in a location update response message. In another case, the ITR and anti-ITR solutions were integrated to help a VPMN operator retain the inbound roamer from leaking to other VPMNs. In one or more of the above solutions, a rejection error message that the HPMN HLR sends to the competitor VPMN, helps the VPMN operator to retain its inbound roamer. This rejection error message causes a failure of the inbound roamer's registration process with the competitor VPMN, and is usually termed as HPMN HLR abort.
However, the prior art TR, ITR anti-TR and anti-ITR techniques did not cover the scenario where a competitor VPMN VLR, instead of the HPMN HLR, aborts the registration attempt of the inbound roamer at the competitor VPMN. As the competitor VPMN VLR aborts the registration attempt, it is referred to as competitor VLR abort. Moreover, one or more of the above mentioned solutions did not consider the case when the inbound roamer's handset got stuck either during his registration attempt at the competitor VPMN or after his successful registration with the competitor VPMN.
In accordance with the foregoing, there is a need in the art for a system and method which allow a VPMN operator to perform traffic redirection on the inbound roamers, in order to cause the VLR of the competitor VPMN to abort the inbound roamer's registration attempt at the competitor VPMN. This helps the VPMN operators to retain its inbound roamers. There is also a requirement to alleviate the problem of stuck handset, as described above.